The most common and most likely answer to this crossword clue is the 10 letter word RACONTEUSE
I've seen this crossword clue in The Times
R
A
C
O
N
T
E
U
S
E
Buddy explains!

The straight part
We know that "story-teller" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case story-teller = raconteuse.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
Crossword Answer definitions
RACONTEUSE noun- A female storyteller.